DIY Cornice Box | Step-by-Step Tutorial
**After reading, you will know how to make your own fabric cornice box**
Are you ready to totally change your room for under $100? The window treatments that came with our home were quite boring (check out the before & afters). I knew I wanted to jazz things up a bit, but it was not until I went into a drapery/window treatment design store that I fell in love with the cornice box look.
The designer took me through the different types and all the fabric choices they had to offer. When I had tentatively picked out the type and fabric, she gave me a quote. To say my jaw was on the floor is an understatement. I’m all about spending money on things if they are done right and give me the look I’m really after, but $1400 for two cornice boxes was waaaaayyyy more than I was willing to spend. Instantly, I was sad. I politely thanked the designer and left.
As I often do, I spent the whole car ride trying to justify why I should spend that kind of money and how I was going to convince my husband that it was worth it. Unfortunately and to my dismay, I could not think of one valid justification.
Because I’m a “do it” type person, I ran the gamut on all the ways I could pull this off. The best option I came up with was to build them myself. My dad has done woodworking most of his life, so I called him up. When I need someone to bounce ideas around and have the task actually completed, my dad is always the first call. We planned a strategy meeting (over a few beers of course) and set a date to do the dang thang.
Here is my step-by-step process on how we made two custom cornice boxes for $90 total for a savings of $1310! This DIY project is one of my favorites and way easier than I had thought. I can’t wait to hear what you think!
Disclaimer: This post does include affiliate links for your convenience. This is at NO additional cost to you, but earns me a small commission. To read more, check out our disclosure policy.
Estimated Cost per Cornice Box:
$30 + cost of fabric
Estimated Time per Cornice Box:
Step 1: Measure for your Cornice Box
Before purchasing your materials, you must measure for your cornice box. Always measure at least two to three times before finalizing your numbers. You want to measure the:
- Length (up and down)
- Width (left to right)
- Depth (how far out from the wall)
When measuring the width (left to right), be sure to add an additional 2” on either side of whatever the cornice box will be covering. When measuring the depth, (how far out from the wall), be sure to allow enough clearance for the drapes or window treatment underneath the box to work appropriately. For my cornice boxes, I had a depth of 5" on the window blinds and 5.5" on the sliding door vertical blinds.
When measuring the length (up and down), I took the distance between the top of my sliding door and the ceiling, then cut it in half. The distance between was 27”, so I made my cornice boxes a width of 13”. I rounded down to make the math a bit easier. I believe the typical length is between 12” and 14”, but since you are making these custom, use your measuring tape to visualize what you think will look best. If in doubt, go with my method of cutting the distance in half.
Step 2: Choose Fabric & Order It
Disclaimer: The links below in steps 2 & 3 are affiliate links for your convenience. This is at NO additional cost to you, but earns me a small commission. To read more, check out our disclosure policy.
I’m obsessed with fabric.com. They have so many options and you can sort and filter in so many ways. I did spend some time at Joann Fabrics, but sometimes I feel more overwhelmed with all the options in my face versus the ability to search in a search box. Choose whatever buying method works for you.
I used 100% cotton fabric and found it very easy to work with, but I'm sure you could get away with many different types of fabric. I would avoid super stretchy or silky materials. I ordered 5 yards of fabric for both of my cornice boxes, but this website might be a good place to start if you are having trouble deciding how much. Fabric.com can always help, too!
Step 3: Gather & Purchase All Materials
I have since upgraded some of the tools shown below, but the affiliate links below reflect that change. This isn't the prettiest display of tools, but these are what we used at the time. All the clickable links below are there for your convenience, but I will receive a small commission if you purchase something from them.
- Plywood for:
- 1 Front Piece (fit to your specifications)
- 2 Side Pieces (fit to your specifications)
- 1 Stability Piece (measurement of your front piece minus the width of the side pieces)
- Note: I used a 7/16" sheet of plywood and had Home Depot pre-cut the wood to my measurements. For my window, I used 55" by 13" for the front piece, 5" by 13" for the side pieces, and 3/4" by 1.5" by 54 1/8" for my stability piece. To get the width of the stability piece, I took 55" minus 7/8" because my side pieces were 7/16" thickness.
- 4 - 2" brackets (to attach the side pieces to the front piece)
- 2 - 2.5" brackets (to attach the side pieces to the wall)
- Fabric of choice (to cover all sides of cornice box)
- Roll of Batting
- 20 - 1" Screws
- 4 Drywall Screws & Anchors (to adhere to wall)
Gather at Home
Note: Most of this you will have at home already, but if not, you will have to purchase these as well.
- Pencil (non-mechanical)
- Measuring Tape and/or Ruler
- Handheld Level
- Laser Level (this one is my fav)
- Phillips Screwdriver
- Right Angle Screwdriver
- Staple Gun and Staples
- Stud Finder
- 1/16" Drill Bit
- Adjustable Impact Punch (optional, but useful for many projects)
- Fabric Scissors
- A Buddy to Help You
- Quick-Dry Spackle, Putty Knife, & Paint, if needed
Step 4: Clear Space & Spackle/Paint Holes
Don't mind the poor photo quality above, but before making any marks on the wall, we removed the old window valance and trim. We left the vertical blinds on the sliding door and the regular blinds on the window, but I did change these later.
I would recommend hanging any drapery rods before fully installing your cornice boxes, but it really was not that big of a deal to take them down and put them back up. You just might save yourself a step or two by putting up the permanent window treatments first and then installing your cornice box.
After removing the old valance, we filled the holes with quick-dry spackle. It took 30 minutes to dry before we could paint it, but this gave us a chance to continue on with the rest of the steps below while we waited.
Step 5: Mark Your Measurements on the Wall
The goal here is to mark where the side pieces are going to line up both from the ceiling-down and from the center-out to the ends of the box. We measured 13” down from the ceiling and 2” out from the blinds on either side for our boxes.
We started by using a laser level measuring our 13" down from the wall and marked that line on either side with our pencil. To make sure we liked the way the board lined up, my dad held the unfinished front piece of wood up to the wall where it was going to be installed. This was just for me to get a clear visual on how it was going to look when we hung it. I was looking to see if it seemed balanced with the cabinets and wasn't lopsided top to bottom in any way. All was good!
With the laser level still going, we put the front piece down and measured 2” out on either side of the blinds with our handheld level. I have since upgraded to the crosshatched laser level linked above. I would highly recommend using that to make your vertical line as well as your horizontal because it allows you to keep the measurement level for both.
After drawing these lines on the wall, we put the board up one more time to double check that all the measurements fit the board. We did this step before building the cornice box because it was easier to maneuver the front piece as just a board than when it had all other kinds of phalanges attached to it.
Step 6: Attach Side-to-Front Brackets to the Side Pieces
Time to build! We started by attaching the 2" brackets that are going to connect the side piece to the front piece. Each bracket should go about 2.5” in from each end. Pre-drill holes with a 1/16” bit to make it easier to put the screws in.
We used the screws that came with the brackets, but they were a bit longer than the width of the board. However, it was only slightly, so it didn't mess anything up.
Before tightening the screws all the way, use another flat surface, like the other side piece, to make sure the brackets are flush with the edge. This will make sure that when you attach it to the front piece, there aren't any gaps between the two boards.
Repeat this step for the second side piece as well.
Step 7: Attach Side-to-Wall Brackets to the Side Pieces
Before attaching your side pieces to the front board, you will want to attach your brackets, that will mount your cornice box to the wall, to the side pieces as well. Of course, I could not find a picture from this step, so I drew a diagram above.
The wall mounting brackets are the ones in blue in the diagram. Each side piece should have three brackets attached (2 for attaching to the front piece & 1 to attach to wall) as shown above.
Step 8: Attach Side Piece Brackets to Front Piece
When choosing what side of the front board to make the outward-facing side of the cornice box, you will want to look at the board at eye level. If there is any bow in the wood, make sure the bow is curving in towards the brackets of the side pieces as shown above. This will help the wood to square up when you mount it to the wall.
Once you've determined what side will be the front of the cornice box, attach the two sides by lining them up and pre-drilling the holes with your 1/16" bit. This will be done the same way you attached the brackets to the side pieces. Only this time, you are attaching the brackets/side piece to the front piece. You may want to use a book or flat surface to rest against the outside of the side piece before drilling your holes to make sure all pieces are square.
Step 9: Attach the Stability Piece
The stability piece is going to go at the top of the cornice box (same side where the wall mounting brackets were attached). The stability piece is to make sure your cornice box is sturdy and doesn't start morphing on you over time. It also helps when you go to hang it because the cornice box will be much sturdier.
If you had your wood pre-cut at the hardware store, the stability piece should fit pretty snug in between the two side pieces. My measurements were a little bit off, so we did what any DIYer would do and jimmy-rigged-it (see above). It all worked out though because we were able to add my favorite part... the signature!
On the outside of the side piece, we measured to mark the center of the stability piece with a pencil. We then predrilled our hole and screwed the ends of the stability piece into the side piece. Make sure everything is flush and squared off before marking and drilling.
After attaching the ends of the stability piece, we turned the cornice box over and let it lay flat with the sides hanging off. We then marked and predrilled 3 evenly-spaced holes from the front piece to the stability piece. Our 3 screws went in at the center of the stability piece and 2" off each end.
Step 10: Staple the Batting on All Sides
When adding the batting layer, I found it easier to do this on the floor. I laid the batting down first and then put the front face of the cornice box on top of the batting spaced evenly. I folded the batting up like a present (see diagram above) and stapled every 5" keeping the staples on the interior of the cornice box.
When folding, start with the long edges, then move to the sides. When you cover the sides, try to make sure the side-piece edge that will go against the wall when you mount it is smooth and not bunchy. This will make sure your cornice box lays flat against the wall.
When you cover the wall brackets, cut a slit to allow the brackets to be cleanly visible for when you mount the cornice box. Batting material is malleable, so I was able to stretch it over and poke the bracket through, but a scissors will work fine too.
Step 11: Iron Your Fabric
Depending on how wrinkled your fabric is, it would be a good idea to iron it before attaching it to the cornice box. The last thing you want is to end up with odd creases on your cornice box. Be sure to check the expansive of the internet to iron your fabric with the right settings.
Step 12: Staple Fabric to Cornice Box
Once the batting is attached and your fabric is ironed, you will follow the same protocol for attaching the fabric as you did for the batting. If you are using a patterned material, make sure the pattern is straight and evenly spaced both vertically and horizontally.
When you are stapling a patterned fabric, I would recommend that you staple the same part of the pattern each time and then in between, if necessary. Above you will find a a picture of both the left and right side of my covered cornice box. It is not at all perfect, but when you do this project, folding under the raw edges of the fabric and stapling would clean this up a bit.
This side-by-side picture is a close up of one of the sides of the cornice box. The right side is the top where the bracket is poked through and the left side is the bottom part of the side. The part of the side that is facing up in these pictures is the side that will go against the wall when you hang it in the next step. My batting and fabric was a little puffy, but it still squared against the wall nicely. Just remember, you want the wall side to be as flat as you can get it.
Step 13: Hang Your Cornice Box
Get your buddy! You will need at least two people to make hanging the box less cumbersome. When we were ready to hang the cornice box, one of us held it up from the center on our step ladder and aligned the sides to the lines we had drawn in step 5.
With the punch tool (or a pencil), we made a punch through the bracket holes, where the screws were going to need to go, on both sides. This allowed us to know exactly where we needed to make our pre-drilled holes and set the cornice box down.
At this stage, grab your stud finder and determine if the holes you need to use for your screws will be going through a stud or just the drywall. Double check once or twice to make sure.
If you are going through drywall only, you will want to pre-drill your holes and insert your drywall anchors. If you purchase the drywall anchors that are metal and screw in like I have listed and pictured in step 3, you will not need to pre-drill the holes. The anchors that screw in just need the divot from the punch to start it, then you can use a screw driver to put them in.
If you are going to be screwing your screws into a stud, then you will not necessarily need to pre-drill either. If you use the punch, it will create the divot you need to start your screw. Or, you could start your screw while the cornice box is on the ground, back it out, and then go all the way through when you actually hang the box.
Depending on how much depth you used for the cornice box to come out from the wall, you probably won't have enough room to fit a normal screw driver or drill to mount the cornice box. This is why I would highly recommend purchasing the right angle screwdriver from my materials list.
Once your ready to actually mount the cornice box, have one person hold it from the center again and the other person use the right angle screwdriver (with both hands if possible - a thumb to hold it in place and the other hand to crank the screwdriver), to screw the screws in to the wall. Our cornice boxes were not that heavy, so 1.25" screws worked just fine and have kept the cornice box sturdy to the wall.
Step 14: Revel in the Beauty!
You did it! If you have made it this far, you can stand back and take in the beauty that is your DIY'd fabric covered cornice box! Did you know the definition from definition.com of revel says, "Enjoy oneself in a lively and noisy way, especially with drinking and dancing." Well, be sure to encompass the whole definition when the time comes.
Pictures of the two cornice boxes I made to create this post are below. I hope you enjoyed learning how to make your own DIY fabric cornice box. I would love to see your final product when you complete this project in your home. So, when you do, be sure to tag @myhomierhome on Facebook or Instagram! Until next time!